Anthocyanins from Chinese Bayberry Extract Protect β Cells from Oxidative Stress-Mediated Injury via HO-1 Upregulation

Oxidative stress plays a pivotal role during the islet transplantation procedure, and antioxidant supplementation may protect grafts against oxidative injury. Chinese bayberry is one of six Myrica species native to China, and we demonstrated here that anthocyanins from Chinese bayberry extract (CBE) protect pancreatic beta cells (INS-1) against hydrogen peroxide (H2O2)-induced necrosis and apoptosis. Anthocyanins time- and dose-dependently upregulated heme oxygenase-1 (HO-1) gene expression in beta cells and primary islets. HO-1 knockdown increased H2O2-induced cell death and attenuated the cytoprotective effect of anthocyanins. Anthocyanin treatment activated ERK1/2 and PI3K/Akt signaling, and ERK1/2 and PI3K inhibitors partially attenuated anthocyanin-mediated induction of HO-1. Additionally, beta cells pretreated with anthocyanins displayed a decreased extent of apoptosis after transplantation. In summary, these results suggest that anthocyanins in CBE protect beta cells from H2O2-induced cell injury via ERK1/2- and PI3K/Akt-mediated HO-1 upregulation.